Buro Happold won Best project closure/verification process for Coopers Walk - a residential development in Newham
The monitoring/ closure process ensured that each stage of the project followed best practice (model procedures and Environment Agency guidance on verification reporting) so that the requirements of the statutory process were also met. The initial key to this success was the proper definition of the conceptual site model, which correctly identified the source of the contamination and enabled an appropriate remedial strategy to be formulated.
Throughout the process, a positive and proactive approach was taken with engagement with the local authority (London Borough of Newham) and their specialist advisor (Laboratory of the Government Chemist). The monitoring and verification process was well defined in the remediation statement prepared by Buro Happold, but was flexible enough to readily permit modification to cater for changes to the remediation works (due to structural engineering aspects) and also enable adaptation of the monitoring protocol to ensure accurate measurement of vapour concentrations at both upper and lower ends of the range.
Confined space
The remediation was carried out in confined space (cellars) with potentially hazardous atmospheres. The health & safety of the workforce was therefore a critical element of the remedial strategy. The monitoring of these working conditions, quite properly the responsibility of the contractor, was well supported by the air quality monitoring carried out by Buro Happold and formed an important part of the verification process.
The preparation of the verification report, as short but comprehensive text, supported by photographic, chemical and other data as a series of appendices presented on CD ensures that this report remains accessible over the long term - essential for the future residential use of the site and proper closure of the remediation project.
The monitoring of naphthalene concentrations in air requires care and precision in using the appropriate equipment, particularly when, as in this case, measurement was required at both a very low limit of detection and also at concentrations which could exceed the range of accreditation (the background/ lower limit is very close to the value from which the residential SGV is derived).
Adapting the technique to ensure that there was robust data at either end of this scale proved to be critical in the project's success. Continual calibration of the pumps was also important as even small errors in the pump rate could translate into potentially significant errors in concentrations in air (where measuring at concentrations of less than 1ug/m3).
While the focus of this monitoring and verification was naphthalene in air, it was also important to demonstrate that the residual concentration of naphthalene in the remaining portion of the concrete floor was not a potentially significant source of contamination. This was achieved by sampling and analysis of samples of concrete taken from cellars.
"The nature of the project required a robust approach to verification and this was exemplary." Clive Boyle
